Heating appliance



SeptQZO, H. M. NOBIS; v2,130,927

' HEATING APPLIJANCE Filed Nov. 26, 1935 INVENTOR- fimxey MIA/051's m ATTORNEY.

Patented Sept. 1938 UNITED STATES PATENT orrlce Claims,

This invention relates to heating appliances and in particular to space heaters and domestic water supply heaters.

One of the objects of the invention is the pro vision of a vacuum, vapor or low pressure steam heating system in combination with a hot water heating system, both systems being operated from a single boiler without requiring the need of any secondary heating appliances.

Another object of this invention relates to the provision of a hot water heating system employing radiators or heat convectors for eflecting the transfer of heat and in which system novel means are provided for insuring the rapid circulation of the hot water or other liquid.

Another object of the invention is the provision of an indirect water heater in which an extremely rapid transfer of heat may be effected.

Another object of the invention relates to the provision of a novel method of heating whereby a more rapid and effective transfer of heat may be efiected from a primary heated-fluid to the medium to be heated.

Another object of the invention relates to the provision of an improved method of operating a heat exchange system or water heater employing a primary liquid heater in which the liquid is heated below its boiling point and maintained at or below atmospheric pressure.

A further object of the invention relates to the provision of a simple inexpensive, fool-proof arrangement for effecting the accomplishment of the aforesaid objects.

Stated in general terms, the invention comprehends the provision of a heating appliance comprising a primary heating unit which may be in the form of a boiler, heater or the like and the same may be arranged to utilize any of the fuels, as for example, gas, oil or coal, which are available for this purpose. The boiler is used for the purpose of heating a liquid such as water, although liquids having boiling points above and below that of water may be used, as for example, an alcohol solution which would have a lower boiling point than water, or oil, mercury, glycerine solutions, Dowtherm, brine or saline solutions which illustrate examples of liquids having boiling points higher than that of water.

The liquid is maintained in the boiler at a level somewhat below the top of the boiler, as is customary, so as to provide space in the boiler for both liquid and gases, such as, air, vapor and steam. The heat of the liquid is transferred to the medium to be heated by means of a heat exchange device located on a level above the level cf the liquid in the boiler. The heat exchange dewhich connect it with the boiler, are filled at all times with liquid from the boiler which is maintalned at a pressure other than that in the boiler and they define a thermo-siphon circulating system through which the liquid of the boiler is free to circulate. Due to the different elevations of the heat'exchange device and the boiler, the liquid in the heat exchange device and the com duits connecting it with the boiler is at a lower pressure than is the liquid in the boiler. Because of this fact and for other reasons which will be explained presently, a much faster circulation of liquid through the heat exchange device is effected as the temperature of the liquidv is reduced in the heat exchange device.

It is a well-known fact that air films are formed on the inner surfaces of the radiators and the con duits connecting them with the boiler in low pressure steam and hot water heating systems. By evacuating the radiators, adherent air on metal surfaces is eliminated and better heat transfer and faster circulation is effected. Under ordinary operating conditions, the water and steam in the boiler of a low pressure steam or vapor heating system are in equilibrium with each other for the pressure and temperature maintalned at any time so long as the temperature is above that of the boiling point oi the liquid used.

As the liquid in the boiler moves upwardly toward the radiator, its pressure is reduced and steam or-vapor is produced by the liquid which when coming in contact with the cooler surfaces of the radiator, heat exchange device or heat convector, gives up its latent heat and condenses to a liquid. The column of the liquid in the cold water return line is much heavier than the column of mixed water and vapor or steam in the hot water feed line and much faster circulation of the heating medium of liquid results.

The invention may assume many forms and it is adapted for several different types of installations which may be used singly or in combination one with the other. One example of such a use of the invention, is the indirect heating of domestic supply water, in which case, the heat exchange device may be constructed in the form of a hollow casing located on a level above the boiler for the circulation of the boiler water. The domestic water supply line may be introduced into the casing through a heat exchange coil and as the water passes through the coil its temperature is raised by the heated liquid in the casing.

Steam pressure in the boiler or a suction device as described below, may be utilized to raise the level of the liquid to completely fill the casing of the heat exchange device and the passageways communicating therewith.

The invention is also adapted for use in connection with house heating systems, in which case, the heat exchange device previously described would be in the form of one or more radiators or heat convectors located on a level above the boiler with the uppermost radiator or heat convector connected to a suction pump of either the mechanical or injector type. The pump is provided for the purpose of creating a vacuum to draw water from the boiler into the radiator and the conduits connected thereto and completely fill the same, and after this has been eflected, the pump may be shut down and the system will then be in condition to operate under, thermosiphon circulation.

Due to the reduced pressure or vacuum in the radiator, as compared with the pressure in the boiler which is at or above, atmospheric pressure, it has been found that a more rapid circulation of liquid takes place between the radiator and the boiler than would take place if the boiler,

. radiator and the conduits connecting the radiator with the boiler were completely filled with liquid. At the same time a more efificient transfer of heat through the radiator is eiTected by reason 'of such increased circulation and also by reason of the elimination of the adherent air film inside the radiators and use of the latent heat of the steam which is mixed with the water supplied to the radiator. A

The invention may be utilized in the provision of a combined steam and hot water heating system, in which case, one or more of the radiators are filled with water in the manner previously described and the, remaining radiators are conis, of course, obvious that the indirect water heater may also be used in connection with a house heating installation and examples of such installations will be described in detail presently.

The invention also comprehends the use of liquids other than straight water. The use of a liquid having a low boiling point would permit the operation of the boiler at lower temperatures in order to vaporize in the boileriand condense in the radiator a given amount of liquid. On the other hand, the use of a high boiling point liquid would permit the operation of both the boiler and radiator at higher temperatures. It would appear from the foregoing, that certain advantages are inherent in the use of the diflerent liquids proposed and the particular requirements of any given job will determine the best liquid to use.

When the present arrangement is used as a straight hot water heating system, the steam space which is maintained in the boiler provides an expansion space for the system, thereby eliminating the need of the usual expansion tank located either on a level with the boiler or at a point above the highest radiator.

With these and other objects in view, the in- I vention consists in the novel construction, ar-

rangement and combination of parts, hereinafter illustrated and described in some of its embodi- .ments in the accompanying drawing, and particushowing the application or the invention to a fire tube boiler.

.In the form of the invention illustrated in Fig ure 1, there is shown a boiler i, the liquid level of which is maintained at some distance below the top of the boiler, as is' clearly shown in the drawing. The boiler may be provided with a pressure gauge 2 and a glass gauge tube 3 to indicate the-level of the liquid in the boiler. A conduit ii communicates with the lower portion of the boiler. This conduit is connected to a hollow casing 5 and the casing 5 in turn oom= municates with a conduit 6 which is connected by means of a. pipe I with the interior of the boiler at a point a slight distance below the liquid level thereof.

The lower end 8 of the pipe "l is of reduced cross-section so as to facilitate its application to the boiler and to permit the pipe to be fitted with a cup It for installation in the boiler along with the pipe I. The cup is provided to prevent air and other gases which are removed from the water on heating from getting into the pipe 1 and also for the purposeof providing a liquid seal over the end of the pipe to insure retaining the liquid in the indirect heater in case the level of the liquid in the boiler is inadvertently lowered below the end of the pipe I.

A tortuous conduit H, carried by a cover plate i2 for one end of the casing is fitted within the hollow casing 5 and the ends of the conduit are connected to a cold water pipe I3 and a hot water pipe M, the cold water being heated by reason of its passage through the tortuous conduit which is in contact with hot water from the boiler I. The cold water pipe l3 and the hot water pipe l4 may be connected to the lower and upper levels respectively of a hot water storage tank l5 which is connected with a cold water supply line it at its lower level. The conduit II and the surrounding casing 5 constitute what is commonly referred to as an indirect or exchange water heater.

In certain cases the storage tank may be dispensed with, as where the supplying of large quantities of hot water on quick demand is not necessary, and in such cases, the heater will function as an instantaneous water heater. It'is possible' to use the device in this manner because of the extremely rapid heat transference which takes place in the heater as has been indicated previously.

It is customary in heaters of this type to position the indirect heater at a level below the norinal level of the liquid in the boiler, and the present invention differs from the conventional arrangement by reason of the fact that the indirect heater is carried at a much higher level than is customary. The indirect heater is provided at its highestpoint with a key air vent or valve IT, by means of which air and gases are removed from the heater and liquid may be maintained in the circulating system of theindirect heater at a higher level than the liquid in the liquid is boiled long enough to remove dissolved air and gases. The steam or vapor pressure is then raised sufilciently to force liquid out of the boiler by way of the air vent i1, and when this takes place, the vent is shut tight and the indirect heater may then be used.

Diagrammatiical view, Figure 3, illustrates a steam or vapor heating system in combination with a. hot water system, both systems being operated. from a single boiler 20. The hot water heating system may comprise one or more radiators or heat convectors 2!, 22 and 23 in communication with hot water supply lines 24, 25 and 26 respectively, which comunicatein turn with a manifold 21 in communication with the liquid of the boiler ata point adjacent to, the upper level of such liquid by means of a connection such as used in the indirect water heater previously described.

Cold water return lines 28, 30 and M are connected with the lower portions of the radiators ll, 22 and 23 respectively. These lines are in turn connected to a manifold 32 in communication with the lower portion of the boiler. The upper portions of the radiators 2|, 22 and 23 communicate with a conduit 33. This conduit may be formed from a tubing of small diameter, as for example, one-eighth inch copper tubing and it forms a suction line which is connected at 34 to a siphonic air ejector or other suitable suction pump 35. The air ejector 35 may be operated by means of water under pressure from a supply line 36 under control of a valve 31 and the exhaust water from the ejector is carried away by means of a drain pipe 38.

The suction line 33 may be provided with a shut-off valve Ml and a vacuum gauge 4|. The hot water circulating system may be placed in operation by first exhausting air and gases from the radiators 2|, 22 and 23 and the conduits communicating therewith. When these gases have been removed and when the pressure in the boiler is at, or slightly above. or slightly below atmospheric pressure the said radiators and the conduits which connect them with the boiler are completely filled with water by reason of the pressure in the boiler and the vacuum created in the uppermost part of the system and they will be maintained filled with water as long as air or gases are prevented from getting into the cir cuiating system. Air or gas which becomes trapped in the system may be remdved from time to time in the manner just described and the vacuum gauge 4| will indicate the presence of such air in the system.

The radiators l2 and 43 a.e connected respectively by means of conduits 44 and 45 to a steam or vapor manifold 46 in communication with the boiler 20 at a level above the surface of the liquid therein. Condensate from the radiators l2 and 43 and from the vapor conduit 46 is returned to the boiler by way of a return line 41 which is positioned .so as to provide for the gravity flow of such liquid back to the boiler.

An air relief valve 48 may be provided to relieve air from the conduits l6 and ll. .The boiler 20 may be fitted with an indirect water heater similar to the one previously described and comprising conduits 4 and 6', a casing 5' and a storage tank l5 connected to the direct heaterby means of conduits l3 and I4". The conduit 6 communicates with a key air vent IT. The indirect heater corresponds substantially to the arrangement previously described and illustrated in detail in Figure l, and like numerals to which letters have been affixed, in the case of Figure 2, are used to indicate the corresponding parts ofthe direct heater in the difl'erent views.

Figure 4 illustrates the manner of effecting the upper boiler connections when a fire-tube boiler is used. The number indicates such a boiler having tubes 56 one of which has been removed to allow the reduced section 58 of the pipe 51 and its cup to extend below the liquid level in the boiler. A pipe, such as 62, is used when it is preferred to enter the boiler from the side thereof and entry of air into the pipe during the initial heating of the liquid in the boiler is prevented by providing the pipe with an upturned end 63.

It is apparent from the foregoing that the invention is susceptible of many uses which may be used alone orin combination with one another. As an example of this, the arrangement shown in Figure 3 may be used for the heating of the domestic hot water supply in the summer time, in which case, the valves 5G, 5! and 52 of the lines which connect the boiler with the radiator would be closed oil and the heat of the boiler would be utilized entirely for the heating of water in the storage tank 15. The heating system may employ the circulation of hot water in all of the radiators if desired to the exclusion of vapor heated radiators shown and various liquids other than water may be used in the arrangements described.

The method of eifecting a transfer of heat from one medium to another disclosed herein is not dependent upon the use of any special liquid ..or apparatus. Several different liquids have been indicated as being suitable for use, and various and different forms of apparatus have been disclosed and described for carrying out the method which in its preferred mode of application contemplates the use of a liquid as a means for transferring heat from a lower to a higher level without, however, substantially heating the liquid above its boiling temperature or subjecting it to a pressure substantially above atmospheric pressure.

Furthermore, it is to be understood that the particular forms of apparatus shown and described, and the particular procedure set forth are presented for purposes of illustration and explanation and that various modifications of said apparatus and procedure may be made without departure from the invention as defined in the appended claims.

Having thus described my invention, what I claim is:

1. A heating appliance comprising, a boiler or heater for containing a liquid to be heated and having a normal surface level of liquid at a distance below the top of the boiler so that there is space in the boiler for both liquid and vapor, means for heating the liquid in the boiler, a radiator or heat convector communicating with the boiler at different levels below the surface level of the liquid in the boiler, said radiator being positioned on a level above the surface level of the liquid in the boiler, and. means for continuously maintaining a supply of liquid from the boiler in the radiator including a liquid seal at the upper level of communication between said radiator and said boiler which is adapted to prevent gas and air bubbles rising in the liquid of the boiler from freely entering thereat, the liquid in the radiator being at a lower pressure than the liquid in the boiler.

2. A heating appliance comprising, a boiler or heater for containing a liquid to be heated and having a normal surface level of liquid at a distance below the top of the boiler so that there is space in the boiler for both liquid, and vapor,

means for heating the liquid in the boiler, a casing communicating with the boiler at diflerent levels below the surface level of the liquid in the boiler, said casing being positioned on a level above the surface level of the liquid in the boiler, I

and means at the upper level of communication between said casing and boiler for preventing gas and air bubbles in the liquid of the boiler from freely entering thereat, and conduit means leading to and from said casing for indirectly heating a second liquid,

3. A heating appliance comprising, a boiler for containing a liquid to be heated and having a normal surface level of liquid at a distance below the top of the boiler so that there is space in the boiler for both liquid and vapor, means for heating the liquid in the boiler, a radiator located above the boiler and communicating with the boiler at different levels below the surface level of the liquid. in the boiler, means for continuously maintaining a supply of liquid from the boiler in the radiator comprising a conduit dipping into the upper part of the liquid of the boiler, and means associated with the end of said conduit for preventing air and gas bubbles from the boiler from freely entering into the conduit.

4. A combined vapor and hot water heating system comprising, a low-pressure boiler adapted to be operated when partially filled with liquid, a steam radiator above the liquid level of the boiler, a steam supply conduit and a condensate return conduit connecting said steam radiator with said boiler at points above and below the liquid level in the boiler, a hot water radiator above the liquid level of the boiler, a hot water supply conduit and a cold water return conduit connecting said hot water radiator withv the liquid in said boiler at points one near the top' and the other near the bottom of the liquid in the boiler, suction means in communication with said hot water radiator at or above the top thereof for producing'the establishment of a reduced liquid pressure in the uppermost part of the said hot water radiator, and means for holding the establishment of the said reduced liquid pressure in the uppermost part of the hot water radiator.

5. A combined vapor and hot water heating system comprising, a low-pressure boiler adapted to be operated when partially filled with liquid, a steam radiator above theliquid level of the boiler, a steam supply conduit and a' condensate return conduit connecting said steam radiator with said boiler at points above and below the,

liquid level in the boiler, a hot water radiator above the liquid level of the boiler, a hot water supply conduit and a cold water return conduit connecting said hot water ra'diator with the liquid in said boiler at points one near the top and the othernear the bottom of the liquid in the boiler, and means over the inlet mouth of said hot water supply conduit for preventing gas and air bubbles generated in the liquid of the boiler from freely entering such conduit.

6. A combined vapor and hot water heating system comprising, a low-pressure boiler adapted to be operated when partially filled with liquid, a steam radiator above the liquid level of the boiler, a steam supply conduit and a condensate return conduit connecting said steam radiator with said boiler at points aboveand below the liquid level in the boiler, a hot water radiator above the liquid level of the boiler, a hot water supply conduit and a cold water return conduit connecting said hot water radiator with the liquid in said boiler at points one near the top and the other near the bottom of the liquid in the boiler, means in communication with the upper portion of said hot water radiator for maintaining said radiator, said hot water supply conduit and said cold water return conduit filled with water from said boiler, and means overthe inlet mouth of said hot water supply conduit for preventing gas and air bubbles generated in the liquid of the boiler from freely entering such conduit.

7. The method of operating a heating system comprising a boiler and a heat exchange device located above said boiler and connected therewith at different levels, which method comprises: maintaining a liquid level in boiler at a point above the upper connection of the boiler with said heater exchange device, and below the top of the boiler, maintaining said heat exchange device and its connections with the boiler filled with said liquid, and heating the liquid in the boiler to a temperature below the boiling point thereof at atmospheric pressure while maintaining the pressure on the liquid in the boiler at, or below atmospheric pressure.

8. The method of operating a heat exchange system comprising a continuous liquid circuit including a heat liberating device and a heat generating device connected together by a hot liquid supply conduit and a cold liquid return conduit, each conduit having its lowermost end immersed in the liquid of the heat generating device, to

'effect a liquid seal, which method comprises:

maintaining a liquid in the continuous liquid circult, exposing the upper surface of the liquid in the heat generating device to a vapor pressure of a relatively low value in the neighborhood of the value of the prevailing atmospheric pressure, heating the liquid tocause a circulation through the continuous liquid circuit, so that heat may be liberated from the system as the circulating fluid flows through the heat liberating, device, increasing the said circulation and the liberation of heat by rarefying the air in the uppermost part of the continuous liquid circuit to produce the establishment of a reduced vapor pressure in said uppermost part under that which would prevail therein if the air were not rarefied and being of a lower vapor pressure than that prevailing upon the upper surface of the liquid in the heat generating device, and preventing the air and gas bubbles of the heat generating device from destroying the rarefication of the air in the said tainer for maintaining said heat exchange device and said conduits filled with liquid from said container, and means associated with the liquid entrance end of the supply conduit for preventing air and gas bubbles of the liquid container from freely entering into said supply conduit.

10. The method of operating a heat exchange system comprising a continuous liquid circuit including a heat liberating device and a heat generating device partly filled with a liquid connected together by a liquid supply conduit and a liquid return conduit, each conduit having its lowermost end immersed in the liquid of the heat generating device, to eiIect a liquid seal which method comprises, heating the liquid in the heat generating device to such temperature as to cause a steam pressure above the liquid in the heat generating device to be of suiiicient value to lift a liquid column in the liquid supply conduit and the liquid return conduit to the uppermost part of the continuous liquid circuit, venting the air from the uppermost part of the continuous liquid circuit, until the liquid fills the uppermost part of the continuous liquid circuit, sealing the uppermost part of the continuous liquid circuit and thereby causing the liquid in the uppermost part of the continuous'liquid circuit to be subjected to a reduced liquid pressure under that which would prevail therein if the air were not vented, preventing theair and gas bubbles of the heat generating device from destroying the reduced liquid pressure in the said uppermost part oi! the continuous liquid circuit, and reducing the heating of the liquid in the heat generating device to such range of temperatures as to cause the pressure above the liquid in the heat generating device to be below that originally required to lift the liquid, to the uppermost part of the continuous liquid circuit.

ll. The method of operating a heat exchange system comprising a continuous liquid circuit including a heat liberating device and a heat generating device partly filled with liquid connected together by a liquidsupply conduit and a liquid return conduit, each conduit having its lowermost end immersed in the liquid of the heat gen-' erating device, to eifect a liquid seal which method comprises, lifting a liquid column in the liquid supply conduit and the liquid return conduit to the uppermost part of the continuous liquid circuit by producing a rarefication of the air and the establishment of a liquid pressure in the uppermost part of the continuous liquid circuit at a value lower than the liquid pressure prevailing in the heat generating device, sealing the uppermost part of the continuous liquid circuit and thereby holding the liquid in the uppermost part I -of the continuous liquid circuit at a liquid pressure under that which prevails in the heat generating device, heating the liquid in the heat generating device to cause a circulation through the continuous liquid circuit, so that heat may be liberated from the system as the circulating fluid flows through the heat liberating device, and preventing the air and gas bubbles of the heat gencrating device from destroying the reduced liquid pressure in the said uppermost part of the continuous liquid circuit.

12. The method of operating a heat exchange system comprising a continuous liquid circuit including a heat liberating device and a heat generatingdevice partly filled with a liquid connected together 'by a liquid supply conduit and a liquid return conduit, each conduit having its lowermost end immersed in the liquid oi! the heat generating device, to eilect a liquid seal which method comprises, heating the liquid in the heat generating device to such temperature as to cause a steam pressure above the liquid in the heat generating device' to be of suihcient value to lift a liquid column in the liquid supply conduit and the liquid return conduit to the uppermost part of the continuous liquid circuit, venting the air from the uppermost part of the continuous liquid 1 circuit until the liquid this the uppermost part of the continuous liquid circuit, sealing the uppermost part of the continuous liquid circuit and thereby causing the liquid in the uppermost part of the continuous liquid circuit to be subjected to a reduced liquid pressure under that which would prevail therein if the air were not vented, and reducing the heating of the liquid in the heat generating device to such range of temperatures as to cause the pressure above the liquid in the heat generating device to be below that originally required to lift the liquid to the uppermost part of the continuous liquid circuit.

13. The method of operating a heat exchange system comprising a continuous liquid circuit including a heat liberating device and 'a heat generating device partly filled with liquid connected together by a liquid supply conduit and a liquid return conduit, each conduit having its lowermost end immersed in the liquid of the heat gen erating device, to efl'ect a liquid seal which method comprises, lifting a liquid column in the liquid supply conduit and the liquid return conduit to the uppermost part of the continuous liquid circuit by producing a rarefication of the air and the establishment of a liquid pressure in the uppermost part of the continuous hquid circuit at a value lower than the liquid pressure prevailing in the heat generating device, sealing the uppermost part of the continuous liquid circuit and thereby holding the liquid in the uppermost part of the continuous liquid circuit at a liquid pressure under that which prevails in the heat generating device, and heating the liquid in the heat generating device to bause a circulation through the continuous liquid circuit, so that heat may be liberated from the system as the circulating fluid flows through the heat liberating device.

14. A heat exchange system comprising, a liquid container operated in the neighborhood of atmospheric pressure, a heat exchange device located above said container, supply and return conduits for connecting said device to said container below the liquid level thereof to effect a continuous liquid circuit, means for heating the liquid in the liquid container, means for removing air and producing the establishment of a liquid pressure in the uppermost part of the continuous liquid circuit at a value lower than the liquid pressure prevailing in the liquid container for maintaining said heat exchange device and said-conduits filled with liquid from said container, and means for holding the liquid in the uppermost part of the continuous liquid circuit at a liquid pressure under that which prevails in the liquid container.

15. The method of operating a heat exchange system comprising a continuous liquid circuit including a heat generating device and a heat liberating device located at a higher level than the heat generating device, which method comprises: maintaining a liquid in the continuous liquid circuit by removing air from, and producing the establishment of a liquid pressure in, the uppermost part of the continuous liquid circuit at 'a value lower than the liquid pressure prevailing in the heat generating device, and heating the liquid in the heat generating device to a temperature below the boiling point thereof at atmospheric pressure while maintaining the pressure on the liquid in the heat generating device at or below atmospheric pressure.

- HARRY M. NOBIS. 

